Selenodetic Reference

Description

The selenodetic reference point update was a landmark tracking task that was carried out to provide data for use in precisely determining the location of selected lunar reference points. The inconsistencies in the lunar coordinates of surface features between photomosaics from manned and unmanned lunar missions and those shown on lunar aeronautical charts will be updated from these data. The Command Service Module (CSM) scanning telescope was used for tracking each landmark for approximately a 3-min period. At least four marks were entered into the spacecraft computer on each landmark. The spacecraft computer, operating in programm 22 orbital navigation, intergrated spacecraft attitude, optics shaft/trunnion angles, and other factors to compute the actual lunar latitude and longitude of the landmark by postflight comparison with the spacecraft trajectory. The reference points could then be used to update the existing lunar maps.